Various types of slide lock apparatus have been implemented that lock a slide of a press machine with respect to the main body of the press machine when repairs are to be performed to the machine, repairs are to be performed to a die thereof, or exchange of the die is to be performed, and which prevent the slide from shifting downward.
The slide lock apparatus for a servo press disclosed in Patent Document #1 is a slide lock apparatus that is capable of locking, in any desired position, a large diameter helical gear that drives the slide to go up and down via an eccentric mechanism, by engaging engagement claws with the gear teeth of that gear.
With this slide lock apparatus, three locking units are provided spaced along the width direction of the teeth of the helical gear, engagement claws that can engage with valley portions between the gear teeth of the helical gear are provided at the lower sides of the locking units, and these engagement claws are driven forwards and backwards by hydraulic actuators that are provided within the locking units. When the slide is to be locked, the three locking units are driven simultaneously so that their engagement claws are driven toward their advanced positions, and so that at least one of the engagement claws is engaged in a valley position between two gear teeth; and then, by locking the engagement claw with a ball locking mechanism that includes a steel ball, the helical gear is put into a locked state, so that the slide is locked.
And a safety locking mechanism for a press is disclosed in Patent Document #2.
With this safety locking mechanism, a stationary member through which a shaft member of the press passes is fixed to the main frame, a plurality of reception holes are formed in the stationary member, and a plurality of locking pins are shiftably installed in the reception holes. A locked member that opposes the stationary member in the axial direction from the exterior is fixed to the shaft member, a plurality of recesses are formed as circular arcs in portions of the locked member near its outer circumference and receive the inner peripheral halves of the plurality of locking pins, and a plurality of tooth portions for locking that can receive and stop the locking pins are formed at the end portions of these recesses in the circumferential direction.
Compression springs that bias the plurality of locking pins towards their respective advanced positions are installed in the reception holes. And, when the plurality of locking pins are changed over to their advanced positions, each of some portion of the plurality of locking pins is inserted into one of the recesses, and thereafter, since tooth portions for locking are received and stopped at the end portions of the recesses, accordingly the locked member is locked by the plurality of locking pins so that it cannot rotate, and thereby the shaft member is locked so that it cannot rotate, so that the slide is locked.
In order to make it possible to cancel the locked state described above, an annular fluid pressure cylinder is provided at the opposite side of the stationary member from the locked member, with an annular piston of this fluid pressure cylinder opposing the external peripheral halves of all of the locking pins from the exterior in the axial direction.
When the shaft member and the slide are to be kept in the locked state, the annular piston is held in its retracted position; and, when the lock released state is to be maintained, the annular piston is driven to its advanced position, so that the external circumferential halves of all of the locking pints are pressed toward the reception holes by the annular piston, whereby all of the locking pins are pushed out of the recesses and changed over to their retracted positions, and this state is maintained.
Patent Document #1: JP Laid-Open Patent Publication 2007-245172.
Patent Document #2: U.S. Pat. No. 2,185,551.